The DRM on many documents does not allow printing.
You can check that using ctrl-I (cmd-I on Mac?) while reading the deocument, it will give rights information about the document.
Otherwise, ctrl-P, (cmd-P on Mac?) should work.
Thansk for the help. but it didn't work as my file type is "EPUB". I tried ctrl-P but not worked, is there any other way to have print, thanks.
If you are in ADE (digital editions) you should be able to read a file of type .epub (assuming it is properly authorized).
It is while reading in ADE that need to try ctrl-I/cmd-I to ADE to check the rights.
If you are reading in ADE and ctrl-P/cmd-P doesn't work is it probably because you do not have rights to print the document.